It has been known for some time how to replace worn, or in other ways damaged, joints--for instance joints damaged by rheumatism, by removing a joint end from a bone and replacing this end with an artificial part. These artificial parts include a joint part and a connection part that is inserted into the cavity of the remaining bone. The fastening of the artificial part in the bone has been carried out in different way, for instance, the connection part has been threaded and/or cemented into the bone.
Presently available artificial parts have a number of drawbacks. Firstly, this method of fasteing is comparatively complicated and time consuming. Secondly, with time, great loads, for instance in the vicinity of knee joints and thigh bones, cause an increasing play between an artificial part and bone, which may require a replacement of the artificial part. Change of the artificial part normally involves the shortening of the bone to obtain adequate material in which to fasten the artificial part. After a few replacements of the artificial part, so little of the bone remains that the joint must be made rigid due to the lack of bone material.
A further drawback of the artificial parts known thus far is that the natural formation of blood vessels cannot occur within inner cavity of the bone, which presumably further reduces the life span of the mounting of the artificial part and, thus, of the artificial part itself.